Totally. One needs to consider the WIFM aspect - what's in it for me? for the cocoa farmer - however. If the cocoa farmer roasts the beans, that's likely not of much value for the manufacturer due to food safety (roasting is the kill step, and the likelihood of the beans being recontaminated is very high), as well as loss of control of roasting. If it's meant for localized mfr so the farmer can create his own product - then that's an enabler.
A few years ago my daughter did some work exploring incorporating fresnel lenses into solar dryers to improve efficiencies and was able to achieve significant capacity enhancements as a result. Something like this could be repurposed for drying enhancements - not just for cocoa, but for any food item that requires drying for stabilization - corn, rice, fish, etc. Drying is, after all, simply a low heat roaster..
There are a number of variations on the above theme with regards to solar ovens, often positioned as backcountry, off the grid, or SHTF solutions for cooking food. A safety element to consider with either a solar lens concentrator or a fresnel lens focuser is a high potential to start a fire. Think of it as a really big magnifying glass, and we all know what we did with magnifying glasses as kids during the summer 8-)